(a) Technical Field
The present invention relates to a fuel cell startup apparatus and method, and more particularly, to a fuel cell startup method, by which during an emergency such as when a high-voltage battery mounted on a fuel cell vehicle becomes completely discharged (i.e., the battery is dead), fuel cell startup can be achieved without assistance of a high-voltage power source.
(b) Background Art
Due to recent high oil prices and strict restrictions on CO2 emissions, the vehicle industry has been focusing all their energies on the development of eco-friendly vehicles such as hydrogen fuel cell electric vehicles, pure electric vehicles, etc. Among the eco-friendly vehicles, the hydrogen fuel cell electric vehicle produces electricity through an electro-chemical reaction between hydrogen and the air, and drives a motor with the produced electricity to provide a driving force to the vehicle. To smoothly supply hydrogen and the air to a fuel cell stack, a high-voltage component (e.g., an air blower, a pump, etc.) is used and also for fuel cell startup, a high-voltage part capable of supplying high-voltage electricity is used.
In a conventional internal-combustion engine vehicle (i.e., gasoline and diesel), when a low-voltage battery is completely discharged, power is supplied to the low-voltage battery (e.g., a jump start is applied), thus facilitating startup. However, in an eco-friendly electric vehicle, there is yet not real way to easily “jump start” a high-voltage battery. That is, in a fuel-cell vehicle which is a type of pure electric vehicle, high-voltage electricity is supplied using a high-voltage battery or a super-capacitor in fuel cell startup, but when the battery is dead (i.e., completely discharged) or the battery fails, startup becomes impossible. This requires the driver to call a tow truck and endure very high repair fees and significant inconvenience.
Moreover, a stationary fuel cell supplies a high voltage in startup by using a high-voltage power supply instead of a high-voltage battery. However, also in this case, when the high-voltage power supply is out of order or a power failure occurs, startup also becomes impossible. Furthermore, the stationary fuel cell has limitations in use thereof because an interruptible power supply (UPS) is difficult to use as emergency power source when a power failure occurs in a building.
Considering the difficulties associated with re-startup of a vehicle in the case of complete discharge of a high-voltage battery of a hydrogen fuel cell electric vehicle, a pure electric vehicle, a hybrid electric vehicle, etc., various schemes for re-startup have been proposed, including a high-voltage charge port, etc. However, due to cost of implementation and difficulty in packaging, the high-voltage charge port has not been adopted by any automotive manufacture to date.